


Come With Me

by hes_a_pan



Category: Harry Potter - J. K. Rowling
Genre: Angst, Animagus, Bisexual Female Character, Creature Inheritance, Dragons, F/F, F/M, Fluff, Harry Potter Has a Sibling, Hermaphrodites, M/M, Mates, Multi, Other Additional Tags to Be Added, Size Difference, Smut, True Mates
Language: English
Status: In-Progress
Published: 2019-04-22
Updated: 2019-07-05
Packaged: 2020-01-24 04:17:07
Rating: Mature
Warnings: No Archive Warnings Apply, Underage
Chapters: 3
Words: 5,397
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18563752
Author URL: https://archiveofourown.org/users/hes_a_pan/pseuds/hes_a_pan
Summary: Harry Potter has an older sister. Only she's not all that their parents told them. Follow Margret as she learns of her true self and tries to keep her brother out of trouble.





	1. The First Letter

It started like any other winter day. Margret would get up and make coffee and breakfast, then get her brother up to 'help' her. She did most of the work but made sure her little brother knew how to do it too. Today was a special day, it was her eleventh birthday, and it had snowed heavily the night before. Margret loves the snow, she told her brother, Harry, to watch the food and make sure it doesn't burn. Margret put on her coat, boots, hat and gloves before heading outside to shovel the drive. She also cleaned off the car for her uncle. When she got back in the house, she noticed that everyone had now gotten up. "Good morning uncle Vernon. Good morning aunt Petunia. Mornin' Dudley." She looked at each person as she said their greetings.

The day went as ordinary as any other day. The children of the house stayed home as it was the winter break at school. Margret shovelled the driveways of several of the older people on the street. Aunt Petunia loved that she did this because it reflected well on the family. Margret even got a small cookie as a 'Happy Birthday', she was the second favourite as she was the only girl. Well, she was mostly a girl as she had been born with both male and female private parts. Her Aunt told her to show herself to no one. It was so ingrained in her head she didn't get changed in front of anyone, even when she was much smaller.

 

.- / ..-. . .-- / -- --- -. - .... ... / .-.. .- - . .-.

 

It was now July, Margret started on everything she does in the morning like always. The mail had come early today and when she picked it up, there was something odd about it. In the small stack of long envelopes was a shorter packet, looking at who to give it too she noticed it had her name on it. It had had her address down to the 'room' she slept in. Truthfully, it was a cupboard she shared with her brother. Before going into the kitchen she slipped the letter into her room. She'd read it later when it was safe. She entered the kitchen and handed the mail to Uncle Vernon. "Can I take Harry to the park today?" She asked her Uncle after refilling his coffee cup.

"I suppose it would be all right," he said back.

She smiled and thanked her uncle, then told Harry to get changed while she grabbed her clothes. She would change in the bathroom. Today she picked out a pair of shorts and a t-shirt. Her clothes were always a little too big, but they were better than the ones Harry had. Before they left, she grabbed the letter that she had stashed away.

When they got to the park they sat on the swings and she pulled the letter out of her pocket. She had seen many types of letters but one with a wax seal was one she never got to see. It was an odd crest with a large letter 'H' in the middle of it. She opened it and saw that the paper was the same as the envelope. As she read it over, it seemed like a big joke. She made a mental note to ask Aunt Petunia about it later.

Margret and Harry played at the park for a few hours, when they returned to the house it was time for them to start dinner preparations. "Mag, what was that thing you had earlier?" Harry asked.

"Nothing to worry about, Har." She answered hoping he wouldn't say anything in front of uncle Vernon.

Uncle Vernon would always punish them when things happened around them they couldn't explain. Margret remembered the time when she was sitting in the back garden and there were a bunch of snakes everywhere. Aunt Petunia freaked out because of the hoards of snakes and uncle Vernon gave her a week of grounding. There was also the time she had gotten a bunch of bruises and cuts and they all healed over the course of six hours. She had healed broken bones and even changed the length of her hair. She had gently changed the colour of her hair at one point.

Dinner had gone well and there was no mention of the letter. She knew that uncle Vernon was going out with work friends that night, and she would talk to aunt Petunia after he left. It scared her that aunt Petunia would say that she couldn't go, she had some ideas at how to get her to say 'yes' but it was still a longshot. Margret would do what she could but she was preparing for the worst. For now, she would bide her time.

Harry was in their room reading a book, and Dudley was watching T.V. in his room when Margret asked. "Aunt Petunia, in this morning's mail there was a letter addressed to me. It said that they accepted me into Hogwa-"

"Absolutely not."

"Nobody has to know, we could just say that I'm going to a boarding school. Harry doesn't even have to know. I know it has to be real," she placed the letter on the table, "they addressed it to my room. No one but this family knows that."

"No. That is final." Aunt Petunia picked up the letter and tossed it into the fire.

Margret was sure that this wasn't over. There was still time left, she would go even if not this year but she would go. After that conversation, she retreated to her room and started to read. She heard loud whispers after uncle Vernon go home. She couldn't hear what they said, but she was sure that it was some argument. 

 

.- / ..-. . .-- / -.. .- -.-- ... / .-.. .- - . .-.

 

Margret stood in the kitchen making sandwiches for tea when there was a knock at the door. Dudley was the one that had got the door. On the other side of the door was a stern-looking woman wearing beautiful emerald green robes that reminded Margret of the colour of the ink was on that mysterious envelope. "I must speak to your parents." Said a Scottish voice that was as stern as the woman looked. 

Aunt Petunia went to the door next and invited the woman in. "Would you care for some tea?" Aunt Petunia asked.

"That would be lovely."

"Margret, be a dear and get our guest some tea."

"Yes, Aunt Petunia."

They kept the conversation light until the setting of the tea a moment later when the tone transformed rapidly. "I have come regarding the letter we sent to Ms. Potter the other day. It came to our attention that she had no way to send her acceptance. It also came to our attention that the letter had burned."

"Boys leave," Aunt Petunia blurted, "Margret sit." She pointed to the other side of the couch that the stern lady was sitting on.

"Now, she will not be going when we brought them in it was on the condition that you were not to contact us." Uncle Vernon stated.

"That was not in the letter left. We said that since you were the last living blood relatives of the Potters. With you two being adults and the fact there is over one person, the blood wards would hold better. Trying to tie them to just Ms. Potter could cause some unforeseen troubles. As her mother and father did before it is time for her to join our world at school."

"No, she will not be going." Uncle Vernon said loudly.

"It is time for her to be going, she is eleven and by wizard law, it is time for her to go to school. You could send her to Bauxbatons if you wish. She would have to know French for that to be workable unless you want to homeschool her. If that is the case they will ask you to prove your knowledge of all the subjects or have records of hiring tutors. She would also have to take all the exams in the Ministry office."

"She will not be going." Uncle Vernon drawled as though he thought she didn't understand what he was saying.

"She will go, and I do not appreciate being spoken to in such a manner. We will send someone in two week's time to help her buy her things and she will be on the train to Hogwarts on September first. The train leaves promptly at eleven o'clock from platform nine and three quarters. I will send someone to help you get there." She got up and left.

Margret stayed seated absorbing the information that was just given. She was a witch. Well, the lady never said, she also never spoke her name. It was as though the woman had known either her aunt or uncle or both. Margret got up and started to clear the coffee table. She sent a silent prayer to any god that would listen, that while she studied her brother would be fine. She was most worried that Harry would become even more of a punching bag for Dudley than he already was. She would try to mediate the situations, however, she sometimes ends up with bruises and scrapes from Dudley turning to her. She would always take it as it meant Harry wouldn't have too. She could easily block or dodge his hits. Any bystander could see her lack of effort in the 'dodge' she would do. From experience, she learned that Dudley would get madder if she did absolutely nothing.

Margret stayed in her room for the next two weeks only allowed out to do chores and the single plate of food she got every three days, but sometimes they forgot and she missed the first three meals. Aunt Petunia and Uncle Vernon also decided that since she would move to Dudley's second room. He had kicked up a significant fuss about having to get rid of all the broken stuff inside of that room. It was the night before the mysterious person was coming to take her to get her school stuff. She hardly slept a wink at the prospect of getting out of the house and leaving to a new school. She finally fell asleep a few hours before she would have to get up. She dreamed of the magic she would learn and what the school and magical world were like.


	2. Harry's Letter

**Summary for the Chapter:**

> It's Harry's first year and Margret meets a friend from school.

The thunder cracked above their heads as they lay on the hard, dirty floor of the cabin they got dragged too. It was close to midnight the day before Harry's eleventh birthday. Margret and Harry had drawn a crude-looking cake in the dirt. Beside them, Dudley slept on the lumpy couch with an arm hanging off of the couch. It beeped several times as the watch hit midnight. "Happy birthday Harry. Make a wish." Margret whispered to her little brother. 

A deafening bang sounded out through the tiny shack. The shack shook as someone slammed the door from its hinges and onto the floor. Harry hid behind the fireplace and Margret stood beside him mostly hidden with a tight grip on her wand ready to shield herself and Harry if they needed it. "Couldn't make us a cup o' tea, could yeh? It's not been an easy journey..." said the giant man as he walked over to the couch Dudley was still sitting frozen on.

"Budge up, yeh great lump," said the strange man said.

"Hagrid?" Margret asked in shock.

"Margret, keeping out of trouble I hope. Ah, Harry. I haven't you since you were a baby. Yeh look just like yer dad, but with yer mum's eyes."

Before Margret or Harry could say anything else Uncle Vernon seemed to have found his voice after a strange noise he made. "I demand that you leave at once, sir!" he said. "You are breaking and entering!"

"Ah, shut up, Dursley, yeh great prune," said the giant; he reached over the back of the sofa, jerked the gun out of Uncle Vernon's hands, bent it into a knot as easily as if it had been made of rubber, and threw it into a corner of the room.

Uncle Vernon made a high-pitched squeal like a mouse. Hagrid pulled a slightly squashed box out of one of the seemingly millions of pockets that were in his massive coat. "Harry a very happy birthday to yeh. Got summat fer yeh here — I mighta sat on it at some point, but it'll taste all right." 

Inside the box was a cake with pink frosting that read 'Happy Birthday Harry' in green icing. Margret smiled remembering the one she got for her twelfth birthday. This was the first time Harry had ever gotten his own birthday cake. He smiled down at it and when he looked up, the fireplace had been lit and there was a teakettle on the fire as well as sausages. "Who are you?"

"True, I haven't introduced meself. Rubeus Hagrid, Keeper of Keys and Grounds at Hogwarts." He smiled at Harry.

"Call me Hagrid," he said, "everyone does. An' like I told yeh, I'm Keeper of Keys at Hogwarts — yeh'll know all about Hogwarts, o' course."

"Er — no," said Harry.

Harry apologized when Hagrid looked shocked. "Sorry? It's them as should be sorry! I knew yeh weren't gettin' yer letters, but I never thought yeh wouldn't even know abou' Hogwarts, fer cryin' out loud! Did yeh never wonder where yer parents learned it all?"

"All what?" asked Harry.

"ALL WHAT?" Hagrid thundered. "Now wait jus' one second!"

He had clambered to his feet. In his anger, he seemed to fill the whole shack. The Dursleys were cowering against the wall. Margret looked down in shame. "Do you mean ter tell me," he growled at the Dursleys, "that this boy — this boy! — knows nothin' abou' — about ANYTHING?"

Harry must have thought this was going a bit far. He had been to school, after all, and his marks weren't too bad. "I know some things," he said. "I can, you know, do math and stuff."

But Hagrid simply waved his hand and said, "About our world, I mean. Your world. My world. Yer parents' world."

"What world?"

Hagrid looked as if he was about to explode. "DURSLEY!" he boomed.

Uncle Vernon, who had gone very pale, whispered something that Margret couldn't hear. Hagrid stared wildly at Harry. "But yeh must know about yer mom and dad," he said. "I mean, they're famous. You're famous."

"What? My — my mom and dad weren't famous, were they?"

Margret having finally gotten her voice back said, "They were. You are too, me not so much but still, people know who I am. I'm sorry I didn't tell you, Harry. I should have but they told me not to say anything."

"Oh Margret, yer not to blame fer any of this." 

"Stop. Stop, I forbid you from telling him anything." Uncle Vernon as sternly as he could while he was scared shitless.

"Oh, enough of this. Harry — yer a wizard."

"I'm a... what?"

"A wizard and I'm a witch. Just like Mum and Dad." Hagrid handed Harry the envelope that contained his letter and handed Margret the one that contained her list for her second year.

Harry read over the letter and the first question that came to mind was, "What does it mean 'we await your owl'?"

"Ah," Hagrid exclaimed and pulled out a bird out of his coat along with a piece of parchment and a quill. 

He scribbled out a quick letter and sent it off with the owl. "We swore when we took him in we'd put a stop to that rubbish, he will not be going."

"You knew, you knew I was a — a wizard." 

"Knew!" shrieked Aunt Petunia suddenly. "Knew! Of course, we knew! How could you not be, my dratted sister being what she was? Oh, she got a letter just like that and disappeared off to that — that school — and came home every vacation with her pockets full of frog spawn, turning teacups into rats. I was the only one who saw her for what she was — a freak! But for my mother and father, oh no, it was Lily this and Lily that, they were proud of having a witch in the family!"

She drew a breath and continued her rant. A rant that she had clearly held back for many, many years. "Then she met that Potter at school and they left and got married and had you two, and of course I knew you'd be just the same, just as strange, just as — as — abnormal, and then, if you please, she went and got herself blown up and we got landed with you!"

"Blown up? You said Mum and Dad died in a car crash." 

"CAR CRASH!" roared Hagrid, jumping up so angrily that the Dursleys scuttled back to their corner. "How could a car crash kill Lily an' James Potter? It's an outrage! A scandal! Harry Potter not knowin' his own story when every kid in our world knows his name!"

"But-" Harry started.

"Murdered, Harry. An evil wizard named Lord Voldemort murdered them. He tried to kill you too, but he couldn't kill you. Nobody knows why but you stopped him that night. So many people died; witches, wizards and muggles alike. It still scares people, don't enjoy using his name." Margret quickly said.

"Muggles?"

"Non-magic folk."

"Wait, how did you escape?"

"I had the same question, I found a bunch of letters in my vault and the Potter vaults, I contacted some people they addressed those letters to and it turns out I was in the hospital when it happened. One of their friends made Dad go home and sleep while he watched me. Then Voldy attacked and well you know."

"But what happened to Vol-, sorry — I mean, You-Know-Who?"

"Good question, Harry. Disappeared. Vanished. Same night he tried ter kill you. Makes yeh even more famous. That's the biggest myst'ry, see... he was gettin' more an' more powerful — why'd he go? Some say he died. Codswallop. Dunno if he had enough human left in him to die. Some say he's still out there, bidin' his time, like, but I don' believe it. People who was on his side came back ter ours. Some of 'em came outta kinda trances. Don' reckon they could've done if he was comin' back. Most of us reckon he's still out there somewhere but lost his powers. Too weak to carry on. 'Cause somethin' about you finished him, Harry. There was somethin' goin' on that night he hadn't counted on — I dunno what it was, no one does — but somethin' about you stumped him, all right."

They had talked a while more before turning in for the night. They had a big day tomorrow after all.


	3. The Car

**Summary for the Chapter:**

> Margret and Harry meet an interesting couple of blokes in a flying car.

Margret woke to an engine roaring just outside her window. She once again shared a room with Harry only this one was much bigger even if it was the smallest bedroom. There seemed to be headlights streaming in the window before someone shut them off. Looking out the barred window she saw three familiar faces. She quickly shook Harry awake and smiled at the boys sitting in the car outside of their window. "What are you doing here?" Harry asked in shock.

"Here to rescue you of course. Get your trunks," Ron spoke.

Margret had already prepacked her stuff, and she slid the trunk out from under her bed. It was a few days until they had to leave for school; she had put all of her stuff together beforehand. She softly walked over to Harry and helped him shove everything into his trunk. "All your books," Harry nodded, "Wand, Dad's cloak." He nodded again.

"Stand back," Ron said putting a hook over one of the lower red bars that covered the windows.

They pulled away from the window and with a strong yank, the bars and window had come off of the house. The crashing of metal against the concrete below was deafening in the night's silence. It was a surprise to Margret how none of the neighbours had woken from that sound. She and Harry quickly threw their trunks into the boot of the pale blue Ford Anglia. She grabbed Hedwig and handed her over before pushing Harry into the car.

The clicking of the locks that kept their door shut stopped, and he thrust the door open so hard that it came whipping back at Uncle Vernon. He quickly made his way across the tiny room fuming in a rage. Margret felt a sharp tug on the hair on the back of her head. She got violently yanked away from the window as Harry was climbing in. Uncle Vernon had thrown the petite girl halfway across the room and then grabbed for Harry. She looked at George and he looked back at her dead in the eyes and ever so slightly nodded. Harry had mostly been in the car by the time the car pulled away from the window, this caused Uncle Vernon to fall out of the window into the garden below. When Aunt Petunia and Dudley ran to the window, Margret silently hurried down the stairs and slipped out the backdoor. Uncle Vernon had landed in the front garden making that way much too dangerous to go that way. She, as silently as she could, climbed up the wooden fence of the back garden and landed in the neighbour’s back garden. She smiled when she saw that the gate their gate was ajar. She crouched and softly moved towards the gate. She saw no one outside and slipped out of the garden and onto the pavement. She walked to the end of the street and patted her pockets to find her money pouch. A satisfied smirk came to her face when she realized that she had the bag her friends had given her.

She had met an extremely nice guy that took her around Diagon Alley for the first time. He was tall and handsome and had really nice long ginger hair. He had introduced himself as Bill Weasley. She had held up communication with him even when he was in Egypt. She smiled holding the bag open and reached inside. Her arm disappeared into the small black drawstring bag. Bill said he had put an undetectable expansion charm on it and had even taught her how to do it too. He told her he had stocked it with some things that would keep her safe and would help her. The other friend that had helped with the idea was one of Bill’s younger brothers, Charlie. Charlie had put in more stuff to help her. While there were a lot of practical items like potions, clothes, some ingredients and some charms and enchanted items, there were also lots and lots of books. The topics were everything from caring for different creatures to healing spells to random muggle books that either of the two men had liked.

She pulled her hand out with a great smile when she finally found what she was looking for; it was an old-looking packet of parchment but when used acted like a muggle navigation device. She sighed realizing it would be several hours before she would get to London. She jogged to the closest bus stop and waited. It didn’t take long and before she knew it she was on her way.

Margret rifled through her bag and found a piece of parchment and a pen. She scribbled out a quick note to Fred and George that she would be at the Leaky Cauldron in a few hours, and to not worry about her and to tell Harry that she was okay. She had read about a type of magical artifact called a Vanishing Cabinet and in that time found a spell that would turn any object you wanted into a version of it so long as there was a matching object for the destination. She had made a box for herself and gifted the Weasley twins with the sister box. After gently placing the note inside, she said the incantation quietly and hoped that they would think to check their box regularly.

It was nearly midnight when she finally made it to London. She was certain that she wouldn’t make it and would have to walk. Stepping off of the bus she turned back and thanked the driver before she headed toward the Leaky Cauldron. When she opened the door she smiled at the long-haired ginger sitting at the bar. Bill said he had been walking past the twins’ room when he heard the distinct sound of an object coming through a portal. When he went to investigate, he found the box and the note and decided to come and get her. She laughed at that, typical curse breaker looking into other people's business. Or perhaps it was simply just an older brother thing.

They walked into Diagon Alley and into one of the alleys off of the main street and apparated to the Burrow. Margret had hated the few times she had apparated. She always felt like she was being pulled through a straw. They walked the lane to the house and silently snuck in. Bill put her in Charlie’s room as he was still in Romania for his work. Bill was only home because he was given a few days off and had promised to always go to Diagon with Margret for her school shopping.

She woke up by Bill in the morning and given a fresh pair of clothes that he had grabbed out of her bag. “Hurry and change. You won’t want to miss this.” She just nodded at the wicked smile he gave her.

She pulled on the pair of jeans and a jumper and quickly laced up her trainers. She fidgeted and shifted herself to make her look like there was nothing in her trousers. She bit her lip and analyzed herself incredibly thoroughly; she wasn’t afraid of many things but this had always been the most terrifying. The thought that someone could figure out she was so different, so unusual, such a freak terrified her beyond belief. She looked over herself again and pulled down her jumper a bit more. She opened the door and followed Bill downstairs. When they got down, they stayed out of sight of the door where Harry, Ron and the twins had just come from. Mrs. Weasley came around the corner and started to chastise them for going out and not leaving a note and for taking the car. She snickered when Mrs. Weasley said she didn’t blame Harry. She had said it in such a way that it sounded like he could do no wrong. “Mum, I’m sorry but we have to go back and get Margret.” Fred quickly interjected.

“How incompetent do you think I am?” Magret came into view sounding like he hurt her by his implications.

Both Fred and George glanced at each other and then at the ground before starting to apologize. Both of their heads snapped up when they heard her soft giggles. “Oh, you should have seen your faces. You were terrified.”

“Well, yeah, you could hex us six ways from Sunday, and get away with it.” The twins replied in unison.

She innocently smiled at them and then turned to Mrs. Weasley. “I apologize for being so rude. It’s nice to see you again Mrs. Weasley.”

“Oh Margret, dear. When did you get here?”

“I picked her up at the Leaky late last night. You were asleep when I got back the first time.” Bill answered his Mum’s question while slowly coming into view of everyone else.

“Well, it’s good you both are here. We can go shopping when your letters get here. Breakfast is in fifteen.”

The group of children mingled for a bit. Margret got Bill caught up on her home situation and he told her about the case he was working on. They always went shopping for her school stuff together. He came the first year, and he had come her second year as well. Charlie had made a joke about them making traditions that were more important than her own brother. She hadn’t been there for most of his shopping but she had been there to see him get his wand.

Harry had gotten an owl when they were in Diagon Alley, she was a beautiful snowy owl named Hedwig. Harry had questioned why she hadn’t gotten one, Margret had made some joke about trying to convince Dumbledore to let her keep a phoenix. Harry bought it but Bill ended up questioning her about it later. She told him that she was terrified her Aunt and Uncle would kick her out and she wouldn’t be able to protect Harry if she wasn’t there.

Margret was pulled from her thoughts when Mrs. Weasley yelled that it was breakfast. All the children crowded around the table as she was loading food onto plates. There was a crunching noise as someone walked along the path to the door. With a slight creaking, Mr. Weasley opened the lower half of the split door in the kitchen. It was odd for Margret to hear someone ask Harry who he was, but they all had a right laugh when Mrs. Weasley smacked Mr. Weasley for getting excited when he heard his boys drove his enchanted car.

Squawk! Thud. “Percy, fetch the post, dear,” Mrs. Weasley sighed.

“Looks like they sent us Harry and Margret’s letters as well,”

They all opened their letters, reading over the contents, “This lot ain’t gonna come cheap, mum,” One of the twins sighed.

“We’ll manage.”

They all quickly finished breakfast and grabbed their cloaks. Gathering in front of the fireplace they started talking about who should go first. The first suggestion was for Harry to go but Ron quickly said that Harry had never travelled by Floo before. Ron ended up going first, then Harry went some random place after he mispronounced ‘Diagon Alley’. Margret and Bill took the Floo to Gringotts first, Bill said he had to pick something up for Margret. He said it was a present from him and Charlie. As they walked out of the Floo room, Margret smiled at the goblins they passed. She had always been nice to them and they thanked her for it. The goblins had made sure to get her the best services at the best prices and would sometimes throw in free extras. She was going into her third year at Hogwarts and already had the status of goblin friend.

The two were led into a side room and were told the goblins they would meet with would be there in a moment. They sat quietly chatting with each other until two goblins walked in, one Margret knew to be Argok, the goblin in charge of her accounts. The second was one she didn’t recognize; he placed a small, neatly wrapped dark green package in front of her. “Thank you,” her soft voice carried gently to all members of the room.

He nodded and left the room. “Your birthday present. Open it,” Bill said to her.

She gently opened the wrapping and lifted the lid off of the black box. Margret gasped when she looked inside. It was a beautiful, gleaming silver bracelet in the shape of a snake. The light glinted off the small black gems placed where the eyes would be. She thanked Bill profusely and made a mental note to owl Charlie. “We have one more order of business,” Argok spoke.

He gently pushed two large stacks of letters in her direction. “Your parents said to give you these on your thirteenth birthday. They also said to give you a test for all gifts and creature inheritances that you could come into. We can do it now or later if you would prefer to do your school shopping first.”

“I think we should do school shopping first but there is one more thing,” Bill started, “Mags, I want you to say the words ‘awake, I am your Master, hear me and obey’, okay?”

She nodded looking skeptical but said it none the less. Just then the snake bracelet she had in her hand started to change.


End file.
